wrapping pytest.main() call in the runtests.py; fixing the script exi…

…t code

runtests.py

@@ -1,4 +1,8 @@
 #!/usr/bin/env python
+import sys
 import pytest
 
-pytest.main()
+
+# sys.exit() is required otherwise the wrapper exits
+# with exit code 0, regardless the pytest.main() execution
+sys.exit(pytest.main())